The posterior cruciate ligament (PCL) is located in the back part of the knee joint and connects the tibia and the femur. The PCL can be torn when the knee is abnormally twisted. PCL replacement surgery may be necessary if conventional treatment, such as physical therapy, will not bring back basic function of the PCL prior to injury thereof.
During PCL replacement surgery, an orthopedic surgeon generally replaces the damaged ligament with a graft. After making one or more incisions through the skin of a patient, the surgeon inspects the knee joint and generally removes any remnants of the PCL using an arthroscopic shaver. Tibial and femoral tunnels are then drilled in the tibia and femur respectively in order to provide access locations to anchor the graft. In order to position and tension the graft accurately, the tunnels are drilled using drill guides.
A tibial tunnel is generally drilled diagonally from an anterior portion and exiting a posterior portion of the tibia at a predetermined distance below the tibia plateau. Adjacent the posterior portion of the tibia are delicate tissues such as the popliteal artery and femoral nerve, for example. As a guide pin or drill exits the posterior portion of the tibia after formation of the tibial tunnel, care should be taken by the surgeon so as to not contact and potentially damage these tissues.
The femoral tunnel is generally drilled diagonally from a posterior portion of the femur and exiting an anterior portion of the femur between the femoral condyles. The graft is then generally attached to long sutures and pulled into position through the tibial and femoral tunnels. The graft replacement is generally held into place by bioabsorbable or metallic screws.
While it is important for the surgeon to be able to view the exit location of a guide pin or drill from the posterior portion of a patient's tibia, there exists a need to ensure that delicate tissues, such as the popliteal artery and the femoral nerve, for example, are not damaged as the guide pin or drill exits the tibia.